372 Investigations dealing with Phenomena of "Clot" Formations. 



function of the amount of salt added to the gel ; the larger this amount, the 

 broader the " zone of instability " and the greater the amount of erosion 

 within it. 



3. An erosion curve of similar form is obtained when a non-electrolyte 

 (dextrose) is added to the gel. The sugar is, however, without action when 

 present in the eroding fluid, whether the gel contains added salts or not. 



4. Quantitatively, the chloride solutions in their erosive action differ 

 considerably from one another ; the differences between their action is less 

 marked when present in the gel. The maximal effect, both as regards the 

 breadth of the " zone of instability " and the amount of erosion within this 

 zone, is produced by lithium chloride. The order of action of the salts 

 investigated is LiCl>lS T aCl (generally) >MgCl 2 >KCl. This is the order 

 of their action in increasing the permeability of certain vegetable cells. 



5. Eelatively more calcium chloride is necessary to " antagonise " the 

 erosive action of salts within the " zone of instability " than is necessary to 

 antagonise the same amount of erosive action produced by higher concentra- 

 tions (in the second phase of the erosion curve). 



6. The erosive action of sodium salts other than chloride on the gel 

 containing added chlorides was also investigated, and an erosion curve of 

 diphasic character was always obtained. The form differed for each salt, both 

 as regards the breadth of the " zone of instability " and the amount of 

 erosion. Specially remarkable was the erosion curve produced by sodium 

 lactate on a gel containing potassium chloride. The erosion curve in this 

 case showed a very narrow " zone of instability," with an exceptionally large 

 amount of erosion within the zone. 



7. The general action of salts on a gel system has been discussed, and it is 

 pointed out that it is probably the resultant of several physico-chemical 

 factors acting simultaneously. Attention is also called to the probable 

 complexity of the biological action of salts. - 



